Next multiply the footprint of the roof by the multiplier below for your roof pitch to find the overall roof area.
Multiplier for 3 12 roof.
And for a roof with a slope of 6 12 that number 1 118 is your roof slope multiplier.
Roof is 6 12 pitch and measures at 2 400 square feet so 2400 x 1 12 2 688 2 88 sqs added for pitch.
Divide the rise by the run the run is 12.
Find the value of 7 12 from the roof slope multiplier table which is 1 16.
The calculator above can handle much of this math.
The value arrived at 928 reflects the square feet of the roof.
Roof pitch area multipliers.
That gives you 5 590 square feet which is the actual area of the surface of the roof.
Now divide the rise by the multiplier to get the pitch eg.
Use our roof pitch calculator to find the pitch of your roof.
Also the multiplier is so close to one that it does not really change the total size unless your roof is something like a 100 100.
100 1 054 105 4ft 2.
We included a roof pitch chart below the 7 12 example image and the calculator below that.
Simply locate a roof rafter board place the end of the level against the bottom edge and measure from the 12 inch mark vertically to the bottom edge of the rafter.
A roof pitch multiplier also called a roof pitch factor is a number that is multiplied by the area covered by a sloped roof to produce the area of the actual surface of the roof for roof slopes expressed as x in 12 rise in run the roof pitch multiplier is determined by finding the square root of rise run 1.
We excluded roof multipliers for pitch below 3 and above 12 for the following reasons.
800 multiplied by 1 16.
If the home measures 20 x 40 and has a 7 12 roof then to calculate the slope of the roof follow these steps.
Multiply step 1 and step 2 i e.
48 10 4 8.
For example a 4 12 pitch roof that is 100 square feet.
The pitch of this roof is 4 8 12.
If this isn t practical then perform the same measurement on the underside of the roof.
With pitch under 3 you can easily walk on the roof to get the exact measurements as that is usually a flat roof.
Roof pitch degree table.
Outside of the u s a degree angle is typically used.
It affects walkability as well as drainage and roofs in areas of high rain.
For example if you measure 4 inches the pitch of your roof is 4 12.
This will give you the rise over run or pitch.
For instance a 7 12 roof pitch means that the roof rises 7 inches for every 12 horizontal inches.
Get your roof size by using this roof pitch calculator.
Take the area of the roof s footprint say it s 5 000 square feet and multiply 5 000 by 1 118.
Roof pitch is a determining factor for cost of the roof as well as the roof area and the type of materials used.
Image 1 12 to 12 12 roof pitch 7 12 pitch.